Mesh networking is a way to route data, voice and instructions between nodes of a mesh network. In a mesh network, a connection between a source node and a destination node is arranged through a plurality of relay nodes between them, but routing may be reconfigured around broken or blocked paths by “hopping” from node to node until the destination node is also reached. Mesh networks may be mobile or fixed networks. Mobile ad-hoc networking featured in many consumer devices is one type of a mesh network. Another example of a mesh network is defined in the IEEE 802.16 specifications.
In other words, if the source node has data to be transmitted to the destination node through one or more relay nodes, the source node first transmits the data to a relay node capable of communicating directly with the source node, then the relay node transmits the data further to the next relay node, and so on until the data reaches the destination node. According to medium access control (MAC) of a wireless mesh network, each node of the network has a half-duplex transceiver and, when a source node has data to be transmitted to a neighboring node (a relay node or the destination node), the source node first agrees with the neighboring node on a transmission resource to be used in the transmission of the data. This is carried out during a “beaconing period” in which nodes close to each other reserve transmission resources in a predetermined or randomized order. The transmission resource may include a time interval on a frequency channel, for example.
During the beaconing period, the source node reserving a transmission resource transmits a reservation message to each one-hop neighbor. If a neighboring node is not active, i.e. neither transmitting nor receiving, within the requested transmission resource, it may transmit a positive acknowledgment to the source node. The reservation becomes valid, if the source node receives the positive acknowledgment from all the neighboring nodes. The data is then transmitted from the source node to a given neighboring node within the reserved transmission resource.
The reservation scheme described above lacks flexibility in that only the node having data to be transmitted may make a reservation and, thereby, control data transmission within the reserved transmission resource. Furthermore, transmission of the data is only possible from the node making the reservation.